1. Field of the Invention
The present invention generally relates to improvements in a device designed for indexing a work attached to a cutting device of a machining center at fixed angles.
2. The Description of Prior Art
This kind of device for indexing, wherein a mechanical coupling or an electrical counting device is utilized to index a work at fixed angles, has conventionally been known.
For example, the former is a device adapted for detecting an engagement between a plurality of index holes formed in concyclic positions in an index table and an index plunger, thereby transmitting revolutions of a driving motor through some timing gears into a driving shaft and indexing a work to rotate at fixed angles.
The latter is a device adapted for applying pulse signals to an indexing table by providing a pulse generator and counting the pulse signals by provisions of a counting device, thereby rotating the indexing table from a reference position at fixed angles by a driving motor and indexing a work.
On the other hand, a device for manually indexing the work so as to be adapted for unclamping, indexing and clamping the work, has been known.
The above device for indexing mechanically or electrically must be provided with an indexing table, various devices for actuating the indexing table and the like, for example driving shafts and timing gears. The device has, therefore, some defects which lead to its increased cost due to its large size.
Though a tool of the cutting device is controlled in accordance with the prescribed programming of an NC device, i.e. Numerical Control Device, the above-described device for indexing must be designed for actuating the indexing table, independent of machining, resulting in this machining and indexing being extremely troublesome.
Furthermore, as the prior art indexing table is actuated to rotate electrically, utilizing the other hydraulic or air-pressure source, electrical wirings and hydraulic or air-pressure lines are required. Thus it prevents these wirings and lines from arranging a plurality of pallet changers holding works on the table. This causes a low productivity because a plurality of works cannot be simultaneously machined.